def round_ans(val):
    """
    Round a number to 2 decimal places and return as a string.
    """
    return "{:.2f}".format(round(val, 2))


def to_miles(to_convert):
    """
    Converts kilometers to miles.
    """
    miles = to_convert * 0.62137
    return round_ans(miles)


def to_kilometres(to_convert):
    """
    Converts miles to kilometers.
    """
    kilometers = to_convert * 1.60934
    return round_ans(kilometers)